feat: added helper methods to the context: Provider and Consumer

[ncpa0cpl]

Added two helper methods to the Context object. A Provider and a Consumer are JSXTE Components that provide similar functionality to the React's Context.

Example

const myCtx  = defineContext<{foo: string}>;

const App = () => {
  return (
    <myCtx.Provider value={{ foo: "hello" }}>
      <myCtx.Consumer
        render={cv => <span>{cv.foo}</span>}
      />
    </myCtx.Provider>
  );
};